Implement mounted depth control system

Abstract

A depth control system for controlling the working depth of an implement. The depth control system includes a monitor having an automatic mode of operation and a manual mode of operation wherein the automatic mode of operation provides preset, discrete working depth positions for the implement, and the manual mode of operation provides a continuous range of selectable positions. The monitor receives input signals from a position sensor mounted to the frame of the implement, and the position sensor includes a movable arm in sliding contact with an actuator arm mounted to a rock shaft of the implement whereby movement of the rock shaft and actuator arm causes the movable arm of the position sensor to move and provide different input signals to the monitor corresponding to the different positions of the rock shaft. The monitor provides an output signal to a hydraulic valve for controlling one or more hydraulic cylinders which actuate the rock shaft in movement to position the working depth of the implement. The monitor compares the input signal from the position sensor to an operator selected position, and provides an output signal to the hydraulic valve to cause the hydraulic cylinders to be actuated until the input signal matches the operator selected position. The hydraulic valve, position sensor and actuator arm include brackets for facilitating retrofit of the depth control system to an existing implement.

What is claimed is: 
     
       1. A depth control system for use in combination with an implement having a frame, ground engaging tools, a frame supporting wheel mounted to a rockshaft rotatably supported on the frame, and a cylinder for moving the frame supporting wheel to a desired position to adjust the working depth of the tools, the depth control system comprising: a monitor for receiving an input signal corresponding to the rotational position of a rockshaft on an implement, and for providing an output signal for positioning a frame supporting wheel at a predetermined position relative to an implement frame supported by the frame supporting wheel;   a hydraulic valve connected to said monitor for receiving said output signal in order to control flow of hydraulic fluid to a cylinder connected to the frame supporting wheel whereby the frame supporting wheel is positioned at a predetermined position to provide a desired working depth for the implement;   a position sensor connected to said monitor for providing said input signal to said monitor, said position sensor including a movable sensor arm;   an actuator arm for contacting said movable sensor arm, said actuator arm including a mounting bracket for attaching said actuator arm to the rockshaft of the implement;   said movable sensor arm including a bearing surface, and said actuator arm including a distal end, distal from the rockshaft extending to contact said bearing surface wherein rotation of said actuator arm with said rockshaft about a rotational axis of said rockshaft causes said distal end to slide relative to said bearing surface of said sensor arm resulting in a continuous range of contact points between said bearing surface and said distal end; and   wherein said actuator arm moves said movable sensor arm in response to movement of the frame supporting wheel and corresponding rotation of the rockshaft supporting said actuator arm whereby said monitor is provided with said input signal to enable said monitor to compare the position of the rockshaft corresponding to said input signal to an operator selected working depth for the implement.   
     
     
       2. The system of claim 1 wherein said position sensor comprises a potentiometer providing a continuous range of input signals to said monitor. 
     
     
       3. The system of claim 2 wherein said movable sensor arm is rotatable about a pivot axis such that rotation of said actuator arm causes rotation of said sensor arm about said pivot axis. 
     
     
       4. The system of claim 1 wherein said hydraulic valve includes a solenoid actuated mechanism for alternately configuring said hydraulic valve for an open center and a closed center hydraulic system. 
     
     
       5. The system of claim 1 wherein said monitor includes controls for selectively positioning the frame supporting wheel, said controls providing a plurality of positions for the frame supporting wheel between a position supporting the frame in a fully raised position and a position supporting the frame in a fully lowered position. 
     
     
       6. The system of claim 5 wherein said monitor has an automatic mode of operation and a manual mode of operation, said automatic mode of operation including a plurality of preset, discrete positions for the frame supporting wheel selectable by one of said controls, and another one of said controls operable in said manual mode of operation for moving the frame supporting wheel through a continuous range of positions. 
     
     
       7. The system of claim 1 wherein the mounting bracket of the actuator arm comprises a saddle clamp for extending around the rockshaft of the implement for providing a releasable mounting for said actuator arm whereby the position of said distal end of said actuator arm relative to said bearing surface is adjustable through rotation of said actuator arm relative to said rockshaft. 
     
     
       8. A depth control system in combination with an implement having a frame, ground engaging tools, a frame supporting wheel mounted to a rockshaft rotatably supported on the frame, and an actuator mechanism including a hydraulic cylinder for moving the frame supporting wheel to a desired position to adjust the working depth of the tools, the depth control system comprising: a monitor for mounting on a tractor connected to the implement;   a position sensor mounted to said frame of said implement and connected to said monitor for providing an input signal to said monitor corresponding to a sensed rotational position of said rockshaft;   a hydraulic valve for connection to a hydraulic system for a tractor, said hydraulic cylinder connected to said hydraulic valve and actuated in movement by hydraulic fluid conveyed through said valve, and said valve including a solenoid electrically connected to a switch on said monitor for alternately configuring said valve for open center operation, providing an open flow path through said valve when flow to said hydraulic cylinder is prevented, and closed center operation, preventing fluid flow through said valve when flow to said hydraulic cylinder is prevented; and   wherein said monitor generates an output signal for controlling said actuator mechanism whereby said actuator mechanism is activated to move said frame supporting wheel to an operator selected position.   
     
     
       9. The depth control system of claim 8 wherein said monitor has an automatic mode of operation and a manual mode of operation, said automatic mode of operation including a plurality of preset, discrete positions for the frame supporting wheel, said monitor including a control for selecting each of said preset, discrete positions. 
     
     
       10. The depth control system of claim 9 wherein said monitor includes a control for further selectively activating said actuator mechanism in said manual mode of operation to raise and lower said frame supporting wheel through a continuous range of positions relative to said frame. 
     
     
       11. The depth control system of claim 8 including an actuator arm mounted to said rockshaft and positioned in engagement with said position sensor for conveying movement of said rockshaft to said position sensor. 
     
     
       12. The depth control system of claim 11 wherein said actuator arm is releasably clamped to said rockshaft and is rotatable around said rockshaft for adjusting the position of said actuator arm relative to said position sensor. 
     
     
       13. The depth control system of claim 11 wherein said position sensor includes a movable portion having a bearing surface and said actuator arm is in sliding engagement with said bearing surface. 
     
     
       14. The depth control system of claim 8 wherein said hydraulic valve includes a first solenoid and a second solenoid, said first solenoid actuating said valve to provide a fluid path to said cylinder for moving said frame supporting wheel in a first direction relative to said frame and said second solenoid actuating said valve to provide a fluid path to said cylinder for moving said frame supporting wheel in a second, opposite direction. 
     
     
       15. A depth control system in combination with an implement having a frame, ground engaging tools, a frame supporting wheel mounted to a rockshaft rotatably supported on the frame, and an actuator mechanism for moving the frame supporting wheel to a desired position to adjust the working depth of the tools, the depth control system comprising: a monitor for mounting on a tractor connected to the implement;   a position sensor mounted to said frame of said implement and connected to said monitor for providing an input signal to said monitor corresponding to a sensed rotational position of said rockshaft, said position sensor including a bearing surface;   an actuator arm releasably clamped to said rockshaft and including a distal end, distal from said rockshaft, in contact with said bearing surface of said position sensor, said actuator arm being rotatable around said rockshaft for adjusting a point of contact of said distal end of said actuator arm relative to said bearing surface of said position sensor; and   wherein said monitor generates an output signal for controlling said actuator mechanism whereby said actuator mechanism is activated to move said frame supporting wheel to an operator selected position.   
     
     
       16. The depth control system of claim 15 wherein said position sensor includes a movable sensor arm which is mounted for rotation about a pivot axis. 
     
     
       17. The depth control system of claim 16 wherein said movable arm includes said bearing surface and said distal end of said actuator arm is in sliding engagement with said bearing surface. 
     
     
       18. The depth control system of claim 15 wherein said monitor has an automatic mode of operation and a manual mode of operation, said automatic mode of operation including a plurality of preset, discrete positions for the frame supporting wheel, said monitor including a control for selecting each of said preset, discrete positions. 
     
     
       19. The depth control system of claim 18 wherein said monitor includes a further control for selectively activating said actuator mechanism in said manual mode of operation to raise and lower said frame supporting wheel through a continuous range of positions relative to said frame.